Polyrhythm

Polyrhythm is the simultaneous use of two or more incompatible rhythms. The classic example is ‘three against two’ — one voice plays triplets while another plays duplets, creating two rhythmic streams that don’t align except at certain points. The result is rhythmic complexity that gives the music a particular kind of motion and tension.

Polyrhythm is fundamental to West African musical traditions, where multiple drum patterns interlock to create complex rhythmic textures. Western classical music borrows the device — Brahms uses three-against-two extensively; Stravinsky uses elaborate polyrhythms in The Rite of Spring; modern composers (Carter, Ligeti) build entire works on polyrhythmic structures.

The technique requires precise rhythmic control. Each rhythmic stream must be steady and accurate; the two streams must coexist without one ‘pulling’ the other into alignment. Mastering polyrhythm is one of the great challenges of rhythmic technique.

Greek poly- (‘many’) + rhythmos (‘rhythm’).

Practice each rhythmic stream separately first; then combine. Lock in the underlying pulse; let the two streams play against each other without forcing them to align except at the points where they should.